1. Field of the Invention
The present invention relates to a pressing machine for joining workpieces, and particularly to a pressing machine for joining a metal member and a plastic member of a computer enclosure.
2. Related Art
A conventional computer enclosure is made of metal. A surface of the computer enclosure is often plated or covered with lacquer. Various chemical substances are generally required for plating or lacquering. The processes of surface treatment usually produce waste material.
Thus more and more computer enclosures are being made whereby pre-formed metal members and plastic members are joined together. Typically, a metal member is firstly placed on a plastic member, with hooks formed on the plastic member extending through openings defined in the metal member. The metal member is then pressed downwardly and slid horizontally relative to the plastic member, so that the metal member engages with the hooks of the plastic member. The entire operation is done manually, which is toilsome and time-consuming. Furthermore, there is risk of injury to an operator""s hands.
It is strongly desired to provide a pressing machine for joining two workpieces which overcomes the above problems encountered in the related art.
Accordingly, an object of the present invention is to provide a pressing machine which can easily join workpieces.
To achieve the above-mentioned object, a pressing machine for joining workpieces in accordance with the present invention comprises a workbench, a rigging providing periodic vertical movement, a pair of pressing devices for impacting workpieces and a push apparatus. The rigging comprises a cylinder, a connecting board, and a coupling bar connected between the cylinder and the connecting board. A wedge block is secured under of the connecting board. The wedge block has a pair of protrusions, each protrusion having a first slope. The push apparatus comprises a push block and a pair of guide devices secured on the workbench. The push block has a second slope. A stop screw is secured on the workbench. When the rigging is moved downwardly, the pressing blocks impact the workpieces and the first slopes of the wedge block abut against the second slope of the push block to cause the push block to move toward the workpieces. One workpiece is thereby pushed relative to the other one which is fixed on the workbench. When the wedge block abuts the stop screw, the push block stops pushing the workpiece. The moving workpiece is completely engaged with hooks formed in the stationary workpiece, at corresponding openings defined in the moving workpiece.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of preferred embodiment of the present invention with reference to the attached drawings, in which: